Stainless steel alloys, turbocharger turbine housings formed from the stainless steel alloys, and methods for manufacturing the same

Abstract

Disclosed is an austenitic stainless steel alloy that includes, by weight, about 16% to about 21% chromium, about 4.5% to about 5.5% nickel, about 2% to about 5% manganese, about 1% to about 2% silicon, about 0.8% to about 1.2% tungsten, about 0.4% to about 0.8% molybdenum, about 0.4% to about 0.6% niobium, about 0.4% to about 0.5% carbon, and a balance of iron. The alloy is suitable for use in turbocharger turbine housing applications for temperature up to about 1020° C.

What is claimed is: 
     
       1. An austenitic stainless steel alloy, comprising, by weight:
 about 16% to about 21% chromium; 
 about 4.5% to about 5.5% nickel; 
 3% to 4% manganese; 
 1.3% to 1.7% silicon; 
 about 0.8% to about 1.2% tungsten; 
 0.5% to 0.7% molybdenum; 
 0.45% to 0.55% niobium; 
 about 0.4% to about 0.5% carbon; 
 about 0.03% phosphorous or less; 
 about 0.03% sulfur or less; 
 about 0.01 to about 0.15% nitrogen; and 
 a balance of iron and unavoidable impurities. 
 
     
     
       2. The austenitic stainless steel alloy of  claim 1  comprising about 18% to about 19% chromium. 
     
     
       3. The austenitic stainless steel alloy of  claim 1  comprising about 4.7% to about 5.3% nickel. 
     
     
       4. The austenitic stainless steel alloy of  claim 1  comprising about 0.9% to about 1.1% tungsten. 
     
     
       5. The austenitic stainless steel alloy of  claim 1  comprising about 0.43% to about 0.47% carbon. 
     
     
       6. The austenitic stainless steel alloy of  claim 1 , wherein the austenitic stainless steel alloy further comprises an amount of at least one of boron, calcium, and cerium, wherein said amount, with respect to each such element so-included, is less than about 0.005%. 
     
     
       7. The austenitic stainless steel alloy of  claim 1 , wherein the austenitic stainless steel alloy further comprises an amount of at least two of boron, calcium, and cerium, wherein said amount, with respect to each such element so-included, is less than about 0.005%. 
     
     
       8. The austenitic stainless steel alloy of  claim 1 , wherein the austenitic stainless steel alloy further comprises boron, calcium, and cerium, wherein said amount, with respect to each such element, is less than about 0.005%. 
     
     
       9. An turbocharger turbine housing comprising:
 an austenitic stainless steel alloy, wherein the austenitic stainless steel alloy comprises, by weight: 
 about 16% to about 21% chromium; 
 about 4.5% to about 5.5% nickel; 
 3% to 4% manganese; 
 1.3% to 1.7% silicon; 
 about 0.8% to about 1.2% tungsten; 
 0.5% to 0.7% molybdenum; 
 0.45% to 0.55% niobium; 
 about 0.4% to about 0.5% carbon; 
 about 0.03% phosphorous or less; 
 about 0.03% sulfur or less; 
 about 0.01 to about 0.15% nitrogen; and 
 a balance of iron and unavoidable impurities. 
 
     
     
       10. The turbocharger turbine housing of  claim 9  comprising about 18% to about 19% chromium. 
     
     
       11. The turbocharger turbine housing of  claim 9  comprising about 4.7% to about 5.3% nickel. 
     
     
       12. The turbocharger turbine housing of  claim 9  comprising about 0.9% to about 1.1% tungsten. 
     
     
       13. The turbocharger turbine housing of  claim 9  comprising about 0.43% to about 0.47% carbon. 
     
     
       14. A method of fabricating a turbocharger turbine housing, the method comprising the step of:
 forming the turbocharger turbine housing from an austenitic stainless steel alloy, wherein the austenitic stainless steel alloy comprises, by weight: 
 about 16% to about 21% chromium; 
 about 4.5% to about 5.5% nickel; 
 3% to 4% manganese; 
 1.3% to 1.7% silicon; 
 about 0.8% to about 1.2% tungsten; 
 0.5% to 0.7% molybdenum; 
 0.45% to 0.55% niobium; 
 about 0.4% to about 0.5% carbon; 
 about 0.03% phosphorous or less; 
 about 0.03% sulfur or less; 
 about 0.01 to about 0.15% nitrogen; and 
 a balance of iron and unavoidable impurities.